Refrigerator employing carbon dioxide



Oct.. 4, 1955 A. G. RAYBURN REFRIGERATOR EMPLOYING CARBON DIOXIDE Filed April 14, 1955 hmm/fr United States Patent O REFRIGERATOR EMPLOYING CARBON DIOXIDE Alden G. Rayburn, West Los Angeles, Calif., assignor to Raybrook Co., a joint venture association composed of William H. Brooks, Harry Henke and Alden G. Rayburn Application April 14, 1953, Serial No. 348,640

7 Claims. (Cl. 62-117.55)

My invention relates to means primarily useful for reducing the air temperature in an enclosed space and is especially concerned with a substantially self-contained unit effective to utilize carbon dioxide not only as a refrigerant but also as an actuating medium.

Carbon dioxide gas is customarily made into a compressed ice or snow block commercially sold and utilized as a refrigerant while it sublimes. The resulting carbon dioxide gas usually escapes to the atmosphere somewhat warmer than its normal, solid temperature and thereby serves to carry away heat.

Carbon dioxide is available not only in the form of a compressed block of snow or ice but is also available in the form of liquid under high pressure within containing cylinders or vessels.

It is an object of my invention to provide a refrigerator utilizing liquid carbon dioxide as a refrigerant and as a propulsion medium for the refrigerator machinery.

Another object of my invention is to provide a refrigerator having a plurality of refrigeration circuits, at least one of which is operated by carbon dioxide.

Another object of my invention is to provide a simple and compact mechanism effective to utilize carbon dioxide quite fully in performing refrigerator service.

Another object of my invention is to provide a refrigerator unit which can be for the most part contained within the chamber to be cooled.

Another object of my invention is in general to improve refrigerators.

The particular form of refrigerator chosen for explanation herein is described in greater detail in the accompanying description and is illustrated diagrammatically in the accompanying drawings in which:

Figure l is a diagram of a refrigerator constructed in accordance with my invention, certain portions being broken away to reduce the size of the figure, certain parts being shown out of actual location and various conventional symbols being utilized to illustrate parts of the structure.

Figure 2 is a cross section, the plane of which is indicated by the line 2-2 of Figure 1, the scale being changed.

Although the refrigerator of my invention can quite easily be incorporated in a number of different forms and can be rearranged to adapt it to its particular environment, it is well exemplified in the form shown in the accompanying drawings. In the illustrated arrangement, there is preferably provided one or more flasks 6 or containers of carbon dioxide. These containers are such as to withstand relatively high pressure and are normally supplied almost filled with liquid carbon dioxide, although some carbon dioxide gas is normally present in the upper portions of the flasks. Present commercial flasks contain about 65 per cent liquid carbon dioxide. The flasks are preferably provided with control valves 7. An upper discharge line 8 communicates with the gas space within the flask and a lower discharge line 9 continues as a Siphon tube 11 within the flask nearly to the bottom thereof. By appropriate use of the outlet 8, a gas discharge from the flask is obtained, whereas by use of the outlet 9 a liquid discharge from the flask is obtained. All of the flasks 6 are substantially identical and can be replaced from time to time as their contents are exhausted.

In order to control the output from the flasks 6 I afford an automatic valve 12 preferably actuated by a gas controlled servo cylinder 13. The valve 12 is provided with an outlet conduit 14 and is effective to connect either the upper outlet 8 to the conduit 14 or the lower pipe 9 to the conduit 14 so that the latter conduit can be supplied selectively with gas or with liquid. Preferably, the valve 12 is not only directly actuated by the cylinder 13 but also incorporates a time delay mechanism so that after it has been set to connect the pipe 8 and the conduit 14 that connection is maintained for a predetermined, short interval following which the valve 12 automatically shifts over to disconnect the pipe 8 from the conduit 14 and simultaneously to connect the pipe 9 with the valve 14.

The servo actuator 13 preferably is operated in response to a servo controller 16 supplied with actuating material through a pipe 17, this material being either liquid or gaseous carbon dioxide. Conveniently, a pressure reducer 18 is utilized to cut the pressure of the actuating material to a reasonable value for ordinary use. Connecting conduits 19 and 21 join the actuator 16 with the servo cylinder 13 so that the position of the latter is correctly controlled.

As an impulse to regulate the controller 16, I preferably utilize the temperature existing within the chamber to be cooled and to which a temperature responsive device 22 is sensitive. A line 23 connects the device 22 with the controller 16 so that in practice the valve 12 is regulated so as to control the efllux of carbon dioxide through the pipe 14 at a rate to establish the desired temperature as sensed by the device 22.

Joined to the conduit 14 is a pipe 26 leading from an emergency source of operating gas such as compressed air, nitrogen or the like, connected through a manual valve 27. In the event the carbon dioxide flasks 6 should all become exhausted and be without immediate replacement or replenishment, it is possible by opening the manual valve 27 to supply a temporary actuating material, liquid or gas, through the conduit 14.

Material flowing through the conduit 14 is received in a combined filter and orifice structure 31 (especially illustrated in Figure 2) in which the :incoming fluid, usually liquid, is permitted to expand into gas and to discharge from a nozzle 32. Preferably, the discharge is into the interior of a casing 33 within which a pair of turbine wheels 34 and 36 are situated. The turbine wheels are driven by the jet of material discharging from the nozzle 32 and are utilized to perform useful work as will later be described.

The material discharging from the nozzle 32 tends to form carbon dioxide ice flakes and to build up and in effect solidify on the interior portions of the casing 33 and to interfere with the intended operation of the structure. Consequently, I utilize the bottom portion of the casing 33 as a reservoir for a body 37 of diluent material as alcohol, preferably ethyl alcohol. The diluent material is withdrawn from the body 37 by an alcohol force pump 38 having an inlet check 39 and an outlet check 41. The pump 38 discharges into a tube 42 connected to an appropriate point in the nozzle body 31 so that the alcohol mixes with the incoming and expanding carbon dioxide and so that the efflux from the nozzle 32 is a mixture of rapidly cooled, atomized alcohol and carbon dioxide gas, some of which .still turns into flakes. The net result. however. is that the alcohol prevents the ac- `:retion of large bodies of carbon dioxide snow within the structure and permits the continued operation of the machine.

After it has expanded into gas form within the chamber 33, the gaseous carbon dioxide, carrying some atomized alcohol or alcohol fog with it, flows outwardly through a duct 40 to a rst heat absorber 45 preferably comprised of a plurality of coils of the duct 40 and situated in a location for the absorption of heat from the surroundings; for example, within a room to be refrigerated, and containing the thermally responsive bulb 22. A suitable rotary fan 43 is arranged to circulate air from the refrigerated compartment over the heat absorber 45 in the customary way. The material flowing within the -absorber 45 is particularly effective as a heat transfer agent for the reason that the alcohol droplets contained in it tend to wet the interior of the absorber tubes .42 and to facilitate the transfer of heat to the refrigerant.

After it has traversed the various coils of the first heat absorber 4S, the mixed carbon dioxide and alcohol travels through a discharge pipe 44 into a heat exchanger 46. This is preferably a casing into which the combined material; that is, the carbon dioxide and the alcohol can discharge for heat transfer. The alcohol fog tends to coalesce into a body of liquid and discharges through a drain pipe 47 from the heat exchanger and through a check valve 48 to return to the body 37 of alcohol in ythe bottom of the container 33, thereby completing its circuit. The carbon dioxide entering the heat exchanger 46 has some capacity to absorb further heat and does so Within the heat exchanger, as Will presently appear. The discharge of carbon dioxide from the heat exchanger is 'through a discharge duct 51 leading eventually to the atmosphere through a discharge pipe 52. The carbon `dioxide gas, having started as liquid in the asks 6 and lhaving absorbed heat from various instrumentalities as Yit passes through the refrigerator and having performed mechanical work upon the turbine runners 34, eventually is discharged to the atmosphere through the discharge pipe 52 as spent, after being utilized not only to perform work 'but also to absorb and carry with it heat.

The work done by the carbon dioxide flowing from -the nozzle 32 in turning the turbine runners 34 is utilized for various purposes. The runners 34 and 36 are mounted on drive shafts 61 and 62 having suitable reduction gears 63 and '64 engaged with a drive shaft 66. One end of the drive .shaft is coupled to the fan 43 and rotates it in an appropriate fashion to circulate cooling air.

The other end of the drive shaft 66 is provided with an eccentric mechanism 67 `for operating the plunger 68 of the alcohol pump 38. Between its ends the drive shaft 66 is provided with a plurality of eccentrics 69 and 71 disposed opposite each other on the shaft 66 and coupled by the usual means to a primary piston 72 operating in a large primary cylinder 73 of a compressor generally designated 74 and also coupled to a secondary piston 76 operating in a small secondary cylinder 77 forming part of the compressor.

The compressor 74 is made with an inlet check valve 78 for the admission of a secondary refrigerant to the larger, low pressure chamber 73 from which the compressed refrigerant is discharged through a check valve 81 into the cylinder 77. From that high pressure cylinder the refrigerant is discharged after compression through a check valve 82 into a line 83 extending to a coil 84 Within the heat exchanger 46. The relatively warm secondary refrigerant flowing through the line 83 transfers some of its heat to the discharging carbon dioxide and alcohol primary refrigerant. After having been somewhat cooled in the heat exchanger 46, the secondary refrigerant, which is for convenience ammonia or Freon gas, is released through a duct 86 to a receiver unit 87. In this unit the material is ycarried generally as a liquid body 88. A oat valve 89 regulates discharge of the liquid from the receiver 87.

The secondary refrigerant ilows through a pipe 91 into a secondary heat absorber 93 comprising a group of coils 94, usually situated near the coils 45, and subject to the air circulation induced by the fan 43. The secondary heat absorber 93 therefore assists the first heat absorber 4S in receiving heat from the circulating air. The secondary refrigerant from the coil 94 discharges through `a conduit 96 and returns to the inlet check valve 78 in the primary portion of the compressor. In flowing from the duct 51 to the atmospheric discharge duct 52, the primary refrigerant is made to flow through a jacket 97 surrounding the secondary chamber 77 of the secondary refrigerant compressor so that the carbon dioxide is utilized to absorb even further heat just before being released to the atmosphere.

In the event it is inconvenient or impossible to change the flasks 6, they can be refilled in place through a tilling pipe 98 having a manual control valve 99 therein. This connection can also be used in addition to or in place of the pipe 26 and the valve 27.

In accordance with this arrangement, there is provided a compressor structure for a secondary circulating refrigerant, the compressor being driven by the effect of a primary refrigerant such as carbon dioxide, originally liquid, which is itself utilized as a circulating refrigerant in one heat absorbing structure, the secondary refrigerant being utilized in a secondary heat absorbing structure. In this way, the capabilities of liquid carbon dioxide are utilized very fully not only to perform mechanical work in operating a self contained refrigerating system but also as a heat absorber in supplementing the work of a local circulating system in affording a maximum of heat absorption by the refrigerator.

What is claimed is:

1. A refrigerator comprising a rst heat absorbing unit, a gas motor, a source of liquid carbon dioxideunder pressure, a conduit between said source and said motor, means in said conduit for expanding said liquid into gas for operating said gas motor, a duct connecting the outlet of vsaid motor to said first heat absorbing unit, a heat exchanger, a pipe connecting said rst heat absorbing unit to said heat exchanger, means for releasing gas from said heat exchanger to the atmosphere, a second heat absorbing unit, a refrigerant compressor, means for connecting said gas motor to drive said compressor, means for connecting the outlet of said compressor to an inlet of said heat exchanger, means for connecting an outlet of said heat exchanger to said second heat absorbing unit, and a connector between said second heat absorbing unit and the inlet of said compressor.

2. A refrigerator comprising a rst heat absorbing unit, a source of liquid carbon dioxide, means for converting said liquid carbon dioxide into gas, means for conducting said gas into said first heat absorbing unit, means for releasing said gas from said rst heat absorbing unit to the atmosphere, a second heat absorbing unit, a compressor, means for supplying said compressor with a refrigerant, a receiver unit, means for conducting compressed refrigerant from said compressor through said receiver unit to said second heat absorbing unit, and means operated by said gas in said converting means for operating said compressor.

3. A refrigerator comprising rst and second heat absorbers close together, a fan for driving air over said absorbers, a turbine for driving said fan, means for establishing a jet of carbon dioxide to operate said turbine, means for conducting exhaust carbon dioxide from said turbine to said rst heat absorber, a compressor, means for driving said compressor from said turbine, means for supplying said compressor with a refrigerant, a receiver unit, and means for conducting compressed refrigerant from said compressor through said receiver unit to said second heat exchanger.

4. A refrigerator comprising first and second heat absorbers close together, a fan for driving air over said absorbers, a turbine for driving said fan, means for establishing a jet of carbon dioxide to operate said turbine, means for conducting exhaust carbon dioxide from said turbine to said iirst heat absorber, a compressor, means for driving said compressor from said turbine, means for supplying said compressor With a refrigerant, a receiver unit, means for conducting compressed refrigerant from said compressor through said receiver unit to said second heat exchanger, and means for conducting carbon dioxide from said first heat absorber to coo] said compressor.

5. A refrigerator comprising first and second heat absorbers, a turbine, means for establishing a jet of carbon. dioxide to operate said turbine, means for conducting exhaust carbon dioxide from said turbine to said rst heat absorber, a heat exchanger, means for conducting carbon dioxide from said first heat absorber to said heat exchanger, a compressor, means for driving said compressor from said turbine, means for supplying said compressor with a refrigerant, means for conducting compressed refrigerant from said compressor to said heat exchanger, and means for conducting said refrigerant from said heat exchanger to said second heat absorber.

6. A refrigerator comprising a heat absorber, a fan for driving air over said heat absorber, a turbine for driving said fan, means for esablishing a jet of carbon dioxide to operate said turbine, means for combining alcohol with said carbon dioxide in said jet, means for conducting exhaust carbon dioxide and alcohol from said turbine to said heat absorber, means for discharging said carbon dioxide from said heat absorber to the atmosphere, and means for recovering alcohol from said carbon dioxide prior to said discharge thereof.

7. A refrigerator comprising rst and second heat absorbers, a fan for driving air over said absorbers, a turbine, means for connecting said turbine to drive said fan, means for establishing a jet of carbon dioxide to operate said turbine, a reservoir of alcohol, a pump, means for connecting said turbine to drive said pump, means for conducting alcohol from said reservoir to said pump and to combine with said carbon dioxide in said jet, means for conducting exhaust carbon dioxide and alcohol from said turbine to said rst heat absorber, a refrigerant compressor, means for connecting said turbine to drive said compressor, means for conducting refrigerant from said compressor to said second heat absorber, means for transferring heat from said refrigerant in said refrigerant conducting means to said carbon dioxide and alcohol in said exhaust carbon dioxide and alcohol conducting means, means for separating said alcohol from said carbon dioxide and returning said alcohol to said reservoir, means for returning said refrigerant from said second heat absorber to said compressor, and means for cooling said compressor with said exhaust carbon dioxide.

References Cited in the le of this patent UNITED STATES PATENTS 257,505 McMillan May 9, 1882 262,185 Johnson Aug. l, 1882 2,175,267 Killeffer Oct. 10, 1939 2,380,537 McMechan July 31, 1945 2,383,486 lsenberg Aug. 28, 1945 

1. A REFRIGERATOR COMPRISING A FIRST HEAT ABSORBING UNIT, A GAS MOTOR, A SOURCE OF LIQUID CARBON DIOXIDE UNDER PRESSURE, A CONDUIT BETWEEN SAID SOURCE AND SAID MOTOR, MEANS IN SAID CONDUIT FOR EXPANDING SAID LIQUID INTO GAS FOR OPERATING SAID GAS MOTOR, A DUCT CONNECTING THE OUTLET OF SAID MOTOR TO SAID FIRST HEAT ABSORBING UNIT, A HEAT EXCHANGER, A PIPE CONNECTING SAID FIRST HEAT ABSORBING UNIT TO SAID HEAT EXCHANGER, MEANS FOR RELEASING GAS FROM SAID HEAT EXCHANGER TO THE ATMOSPHERE, A SECOND 